Systems and methods for transverse phacoemulsification

ABSTRACT

The invention is generally directed to phacoemulsification handpiece for providing transverse phacoemulsification. In accordance with one embodiment, a phacoemulsification handpiece is provided having a needle, wherein the handpiece is configured to vibrate the distal end of the needle in a transverse direction power is applied to the handpiece.

This application claim priority to and is a continuation application ofU.S. application No. 11/753,554, filed on May 24, 2007, which is herebyincorporated by reference in its entirety.

FIELD OF THE INVENTION

The field of the invention relates to systems and methods forphacoemulsification, and more particularly to systems and methods fortransverse phacoemulsification.

BACKGROUND OF THE INVENTION

A number of medically recognized techniques are utilized for cataracticlens removal based on, for example, phacoemulsification, mechanicalcutting or destruction, laser treatments, water jet treatments, and soon.

The phacoemulsification method includes emulsifying, or liquefying, thecataractic lens with an ultrasonically driven needle before the lens isaspirated. A phacoemulsification system 5 known in the art is shown inFIG. 1. The system 5 generally includes a phacemulsification handpiece10 coupled to an irrigation source 30 and an aspiration pump 40. Thehandpiece 10 includes a distal tip 15 (shown within the anterior chamberof the patient's eye 1) that emits ultrasonic energy to emulsify thecataractic lens within the patient's eye 1. The handpiece 10 furtherincludes an irrigation port 25 proximal to the distal tip 15, which iscoupled to an irrigation source 30 via an irrigation line 35, and anaspiration port 20 at the distal tip 15, which is coupled to anaspiration pump 40 via an aspiration line 45. Concomitantly with theemulsification, fluid from the irrigation source 30, which is typicallyan elevated bottle of saline solution, is irrigated into the eye 1 viathe irrigation line 35 and the irrigation port 25, and the irrigationfluid and emulsified cataractic lens material are aspirated from the eye1 by the aspiration pump 40 via the aspiration port 20 and theaspiration line 45.

Turning to FIG. 2, a functional block diagram of a phacoemulsificationsystem 100 known in the art is shown. The system 100 includes a controlunit 102 and a handpiece 104 operably coupled together. The control unit102 generally controls the operating parameters of the handpiece 104,e.g., the rate of aspiration A, rate of irrigation (or flow) F, andpower P applied to the needle, and hence the eye E. The control unit 102generally includes a microprocessor computer 110 which is operablyconnected to and controls the various other elements of the system 100.The control unit 102 may include an aspiration pump, such as a venturi(or vacuum-based pump) or a variable speed pump 112 (or a flow based orperistaltic pump) for providing a vacuum/aspiration source, which, inthe case of a variable speed pump 112, can be controlled by a pump speedcontroller 116. The unit 102 further includes an ultrasonic power source114 and an ultrasonic power level controller 118 for controlling thepower P applied to the needle of the handpiece 104. A vacuum sensor 120provides an input to the computer 110 representing the vacuum level onthe output side of the pump 112. Venting may be provided by a vent 122.The system 100 may also include a phase detector 124 for providing aninput to the computer 100 that represents the phase between a sine waverepresentation of the voltage applied to the handpiece 104 and theresultant current into the handpiece 104. Further disclosure about thephase detector 124 can be found in U.S. Pat. No. 7,169,123 toKadziauskas et al., which is incorporated herein in its entirety byreference. The functional representation of the system 100 also includesa system bus 126 to enable the various elements to be operably incommunication with each other.

Turning to FIG. 3, the cross-section along the longitudinal axis of aportion of a phacoemulsification handpiece 200 known in the art isshown. Generally, the handpiece 200 includes a needle 210, defining alumen that is operatively coupled to the aspiration pump 40 (FIG. 1),forming an aspiration line 214. The proximal end of the needle 210 iscoupled to a horn 250, which has its proximal end coupled to a set ofpiezoelectric crystals 280, shown as three rings. The horn 250, crystals280, and a proximal portion of the needle 210 are enclosed within ahandpiece casing 270 having an irrigation port coupled to an irrigationline 290 defining an irrigation pathway 295. The irrigation line 290 iscoupled to the irrigation source 30 (FIG. 1). The horn 250 is typicallyan integrated metal, such as titanium, structure and often includes arubber O ring 260 around the mid-section, just before the horn 250tapers to fit with the needle 210 at the horn's 250 distal end. The Oring 260 snugly fits between the horn 250 and the casing 270. The O ring260 seals the proximal portion of the horn 250 from the irrigationpathway 295. Thus, there is a channel of air defined between the horn250 and the casing 270. Descriptions of handpieces known in the art areprovided in U.S. Pat. Nos. 6,852,092 (to Kadziauskas et al.) and5,843,109 (to Mehta et al.), which are hereby incorporated by referencein their entirety.

In preparation for operation, a sleeve 220 is typically added to thedistal end of the handpiece 200, covering the proximal portion of theneedle 210 (thus, exposing the distal tip of the needle), and the distalend of the irrigation pathway 295, thereby extending the pathway 295 anddefining an irrigation port 222 just before the distal tip of the needle210. The needle 210 and a portion of the sleeve 220 are then insertedthrough the cornea of the EYE to reach the cataractic lens.

During operation, the irrigation path 295, the eye's chamber and theaspiration line 214 form a fluidic circuit, where irrigation fluidenters the eye's chamber via the irrigation path 295, and is thenaspirated through the aspiration line 214 along with other materialsthat the surgeon desires to aspirate out, such as the cataractic lens.If, however, the materials, such as the cararactic lens, are too hardand massive to be aspirated through the aspiration line 214, then thedistal end of the needle 210 is ultrasonically vibrated and applied tothe material to be emulsified into a size and state that can besuccessfully aspirated.

The needle 210 is ultrasonically vibrated by applying electric power tothe piezoelectric crystals 280, which in turn, cause the horn 250 toultrasonically vibrate, which in turn, ultrasonically vibrates theneedle 210. The electric power is defined by a number of parameters,such as signal frequency and amplitude, and if the power is applied inpulses, then the parameters can further include pulse width, shape,size, duty cycle, amplitude, and so on. These parameters are controlledby the control unit 102 and example control of these parameters isdescribed in U.S. Pat. No. 7,169,123 to Kadziauskas et al.

In a traditional phacoemulsification system 100, the applied electricpower has a signal frequency that causes the crystal 280, horn 250, andneedle 210 assembly to vibrate at a mechanically resonant frequency.This causes the needle 210 to vibrate in the longitudinal direction witha maximum range of motion, which many consider to be the state where theneedle's cutting efficacy is at its maximum. However, there are a coupleof known drawbacks. First, at this frequency, maximum power is appliedto the needle that results in maximum heat introduced into the eye,which can cause undesirable burning of eye tissue. Second, thelongitudinal motion can cause the material being emulsified to repelaway from the needle, which is undesirable when the goal is to keep thematerial close to the needle to be aspirated (a quality often referredto as the needle's or handpiece's “followability”).

To address the first issue, the power can be applied in pulses, wherelittle or no power is applied in between the pulses, thus reducing thetotal amount of power and heat applied to the needle 210. To address thesecond issue, the power can be applied to the handpiece 200 to cause theneedle 210 to vibrate in the transverse direction. An example of thisapproach is described in U.S. patent application Ser. No. 10/916,675 toBoukhny (U.S. Pub. No. 2006/0036180), which describes causing the needle210 to vibrate in a torsional or twisting motion, which is a type oftransverse motion. This application describes applying to the power tothe needle 210 with a signal that alternates between two frequencies,one that causes longitudinal motion, and one that causes torsionalmotion with a particular type of horn having diagonal slits. Thissolution does provide for followability, but cutting efficacy leavesmuch for improvement.

Accordingly, an improved system and method for phacoemulsification isdesirable.

SUMMARY OF THE INVENTION

The invention is generally directed to phacoemulsification handpieces,and more particularly to handpieces for providing transversephacoemulsification.

In accordance with one embodiment, a phacoemulsification handpiece isprovided having a needle, wherein the needle has a distal end and aproximal end, and wherein the needle is configured to vibrate the distalend in at least a transverse direction when power is applied to thehandpiece; and a horn, wherein the horn has a distal end configured toengage the proximal end of the needle and wherein the horn has one ormore notches distributed around an outer surface of the horn.

In accordance with other embodiments, phacoemulsification handpieceswith needles are provided, wherein the systems are configured to causethe needles to vibrate in a transverse direction when power is appliedto the handpiece.

Other systems, methods, features and advantages of the invention will beor will become apparent to one with skill in the art upon examination ofthe following figures and detailed description. It is intended that allsuch additional systems, methods, features and advantages be includedwithin this description, be within the scope of the invention, and beprotected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to better appreciate how the above-recited and other advantagesand objects of the inventions are obtained, a more particulardescription of the embodiments briefly described above will be renderedby reference to specific embodiments thereof, which are illustrated inthe accompanying drawings. It should be noted that the components in thefigures are not necessarily to scale, emphasis instead being placed uponillustrating the principles of the invention. Moreover, in the figures,like reference numerals designate corresponding parts throughout thedifferent views. However, like parts do not always have like referencenumerals. Moreover, all illustrations are intended to convey concepts,where relative sizes, shapes and other detailed attributes may beillustrated schematically rather than literally or precisely.

FIG. 1 is a diagram of a phacoemulsification system known in the art.

FIG. 2 is another diagram of a phacoemulsification system known in theart.

FIG. 3 is a diagram of a phacoemulsification handpiece known in the art.

FIGS. 4 a, b, c, and d are drawings of phacoemulsification needles inaccordance with preferred embodiments of the present invention.

FIG. 5 a and b are drawings of phacoemulsification needles in accordancewith preferred embodiments of the present invention.

FIG. 6 is a drawing of a phacoemulsification needle in accordance with apreferred embodiment of the present invention.

FIG. 7 is a plot of the 90-degree phase shift between the sine waverepresentation of the voltage applied to a piezoelectricphacoemulsification handpiece and the resultant current into thehandpiece.

FIG. 8 a is a plot of the phase relationship and the impedance of apiezoelectric phacoemulsification handpiece.

FIG. 8 b is a plot of the range of transverse motion with respect tofrequency.

FIGS. 9 a and b are drawings of phacoemulsification footswitches.

FIGS. 10 a, b, and c are drawings of phacoemulsification horns inaccordance with preferred embodiments of the present invention.

FIG. 10 c is a plot of the phase relationship and the impedance of apiezoelectric phacoemulsification handpiece in accordance with apreferred embodiment of the present invention.

FIG. 11 is a drawing of a phacoemulsification horn.

FIG. 12 is a drawing of a phacoemulsification horn.

FIG. 13 is a drawing of a phaco emulsification horn.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

What are described below are preferred embodiments of phacomulsificationsystems and handpieces and methods of use thereof.

Referring to FIG. 3, as mentioned above, there are existingphacoemulsification systems that enable the distal end of the phaconeedle 210 to ultrasonically vibrate in a direction of the longitudinalaxis of the handpiece 200, i.e., in the z direction, which providesoptimum cutting efficacy but may cause less than optimum followability.There are also systems that enable the distal end of the phaco needle210 to ultrasonic vibrate in a direction that is transverse of thelongitudinal axis of the handpiece 200, in the x and/or y direction,which provides followability but less than optimum cutting efficacy.There further are systems that enable the distal end of the needle 210to alternate between one type of direction and another by alternatingbetween two different pulses of energy applied to the handpiece 200,each pulse having different signal frequencies. However, it may bedesirable to enable the distal end of the needle 210 to move in both thetransverse (x and/or y) and longitudinal (z) within a single pulse ofenergy or from power applied to the handpiece 200 having a singleeffective operating frequency, i.e., a frequency that may slightly shiftdue to conditions such as tuning, e.g., an effective operating frequencyof 38 kHz may shift + or −500 Hz. A phacoemulsification system 100 thatcan achieve this gains the benefit of both followability and cuttingefficacy.

There are two aspects of a phacoemulsification system that canindividually or collectively enable both transverse and longitudinalultrasonic vibration, (1) the structure of the handpiece 200 includingthe needle 210 and the horn 250, and (2) the computer readableinstructions within the control unit 102. With regard to the structureof the handpiece 200, there are two aspects to the structure that canindividually or collectively facilitate the desired outcome. First isthe handpiece 200 center of mass relative to its longitudinal axis, andsecond is the structure of the handpiece 200 at the nodes and anti-nodesof the handpiece 200.

Turning to FIG. 4 a, a needle 1000 is shown in accordance with apreferred embodiment of the invention. The needle 1000 is configured tobe coupled to the distal end of an ultrasonically vibrated horn, e.g.,250. The needle 1000 includes a distal tip 1010 defining a lumen 1005for aspiration, a needle base 1020 proximal to the tip 1010, and aneedle interface/adapter 1030 to couple the needle with the horn, e.g.,250. Conventional needles, e.g., 210, have a center of mass located onits longitudinal axis. The needle 1000 has a structure with a center ofmass that is off from the longitudinal axis. This is achieved by havingan asymmetric needle base 1020.

Turning to FIG. 4 b, a cross-sectional view of the needle 1000 is shownfrom the direction i, as indicated in FIG. 4 a. The needle base 1020 hasa portion of mass etched out, leaving a portion 1027, creating anasymmetric configuration. Alternative needle base configurations 1035,1045, and 1055 are shown in FIGS. 4 c, 4 d, and 4 e respectively. FIG. 4e showing an asymmetric needle base 1055 having a single sidesubstantially carved out or flattened.

Turning to FIG. 5 a, another needle 2000, having a distal tip 2010, base2020, and needle interface/adapter 2030, is shown with a center of massoff from the longitudinal axis. In the alternative, or in addition to,the asymmetric base 1020, the needle 2000 can have an off-centerinterface/adapter 2030. Turning to FIG. 5 b, a cross-sectional view ofthe needle 200 is shown from the direction ii, as indicated in FIG. 5 a.The interface/adapter 2030 is concentric with but off-center with theaspiration line 2005.

Turning to FIG. 6, another needle 3000, having a distal tip 3010, base3020, and needle interface/adapter 3030, is shown with a center of massoff from the longitudinal axis. In addition to, or in the alternative,to the embodiments described above, though the outside surface 3015 ofthe needle 3000 is parallel with the longitudinal axis, the aspirationline 3005 is configured to be angled with respect to the needle's 3000longitudinal axis.

As mentioned above, the control unit 102 can also contribute toproviding transverse and longitudinal motion of the needle, e.g., 210,1000, 2000, and 3000. The typical range of frequencies used for aphacoemulsification system 100 is between about 30 kHz and about 50 kHz.The frequency used often depends upon the structure of the handpiece 200and many systems 100 are designed to apply a frequency corresponding tothe resonant frequency of the handpiece 200, which, as explained above,causes the needle 210 to vibrate in a maximum longitudinal range ofmotion. When the frequency applied to the handpiece is significantlyhigher, or lower than resonancy, it responds electrically as acapacitor. The representation of this dynamic state is shown in FIG. 7in which curve 60 (solid line) represents a sine wave corresponding tohandpiece 30 current and curve 62 (broken line) represents a sine wavecorresponding to handpiece 30 voltage.

Turning to FIG. 8, as is known in the art, the impedance of the typicalphacoemulsification handpiece 200 varies with frequency, i.e., it isreactive. The dependence of typical handpiece 30 phase and impedance asa function of frequency is shown in FIG. 8 a in which curve 64represents the phase difference between current and voltage of thehandpieces function frequency and curve 66 shows the change in impedanceof the handpiece as a function of frequency. The impedance exhibits alow at “Fr” and a high “Fa” for a typical range of frequencies.

Some conventional phacoemulsification systems 100 apply power to thehandpiece 200 at Fr (point A) which generally causes the needle 210 tovibrate in the longitudinal direction. In one approach, particularlywith the needles described above, 1000, 2000, and 3000, it may bedesirable to move the signal frequency of the power applied to thehandpiece 200 up to point C. The frequency applied at point C causes theneedle, e.g., 210, 1000, 2000, and 3000, to effectively vibrate both inthe z direction as well as the x and/or y direction (i.e., sustained andsubstantial vibration as opposed to transitional vibration, such asvibration that could occur when the power signal shifts from onefrequency causing longitudinal movement to a second frequency causingtransversal movement, or incidental vibration, such as any minimaltransversal vibration when the needle is predominantly vibrating in thelongitudinal direction). It was determined that the ratio of range ofmotion between the longitudinal and the transverse direction isapproximately 1:1 with about 0.75 to 1 mil range of motion in bothdirections, which provides the operation of the needle with effectivefollowability and cutting efficacy. However, power usage at thisfrequency is less than a Watt, so the longitudinal range of motion iseffective but limited, and thus, so is the cutting efficacy. To increasethe cutting efficacy, the impedance can be increased, which can beachieved by moving the operating frequency down to point B, where thelongitudinal range of motion increases, thereby increasing cuttingefficacy. Turning to FIG. 8 b, the amount of transverse motion isgraphed relative to the frequency from point C to point B. This showsthat the range of transverse motion increases as the frequency decreasesup to a certain point before reaching point B, and then the transversemotion range saturates at a point between point B and point C, C'. Forthe standard WhiteStar™ handpiece, the Fr is approximately 36.6 kHz, Fais approximately 37.1 kHz, point B is approximately 37.2 kHz, and pointC is approximately 37.8 kHz.

A surgeon can control these various types of vibrations by using afootswitch that is coupled with the control unit 102. With reference toFIG. 9 a there is shown apparatus 80 for controlling a handpiece 200during surgery which includes a foot pedal 12 pivotally mounted to abase 14 for enabling a depression thereof in order to provide controlsignals for handpiece 200 operation. A foot pedal 12 may be similar oridentical to known foot pedals such as, for example set forth in U.S.Pat. No. 5,983,749, issued Nov. 16, 1999 for Duel Position Foot Pedalfor Ophthalmic Surgery apparatus or U.S. patent application Ser. No.09/140,874 filed Aug. 29, 1998 for Back Flip Medical Foot Pedal.

Support surfaces in the form of shrouds 29, 22 may be provided anddisposed adjacently foot pedal 12 on opposite sides 26, 31 at a positionenabling access thereto by a user's foot (not shown). The first andsecond foot activated ribbons switches 34, 36 to are disposed on thesurfaces 29, 22 in a conventional manner such as gluing or the like, andhave a length extending along the surfaces 29, 22 which is sufficient toenable actuation of the ribbon switches 34, 36 by a user's foot (notshown) without visual operation thereof by the user (not shown). Moredetail about this footswitch 80 can be found in U.S. Pat. No. 6,452,123to Jerry Chen, which is hereby incorporated in its entirety.

As can be appreciated by one of ordinary skill in the art, thefootswitch 80 can be configured to control the longitudinal vibration ofthe distal end of the needle 210, 1000, 2000, and 3000 with the pitchmovement of the footpedal 52 via the control unit 102 by associating thepitch movement of the foot pedal 12 with the power level and transversevibration of the distal end of the needle 210, 1000, 2000, and 3000 witheither ribbon switches 36, 36.

Turning to FIG. 9 b, another footswitch 26 in accordance with apreferred embodiment is shown. The footswitch 26 includes a base 48, twoside switches 56, a data and/or power cable 28 to couple the footswitch26 to the control unit 102 (a wireless interface known in the art, suchas Bluetooth, can also be employed), and a footpedal 52 that allows forboth pitch and yaw movement. As can be appreciated by one of ordinaryskill in the art, the footswitch 26 can be configured to control thelongitudinal vibration of the distal end of the needle 210, 1000, 2000,and 3000 with the pitch movement of the footpedal 52 via the controlunit 102 by associating the pitch movement of the footpedal 52 with thepower level and transverse vibration of the distal end of the needle210, 1000, 2000, and 3000 with either the yaw movement of the footpedal52 or the side switches 56. For example, the yaw movement of thefootpedal 52 or the side switches 56 can be associated with thefrequency of the power applied to the handpiece 200. In a furtherexample, the yaw movement of the footpedal 52 can be associated with therange of frequencies between point B and point C in FIG. 8 b. Inaddition, the side switches 56 can be used to allow the surgeon totoggle between using point A, where cutting efficacy is at its optimum,and using a frequency between point B and point C, where transversemotion can be controlled by the yaw movement of the footpedal 52.

In addition to, or in the alternative to, the needle structure, e.g.,210, 1000, 2000, and 3000, transverse and simultaneoustransverse/longitudinal vibrations can further be achieved through thestructure of the horn 250 and piezocrystal stack 280 configuration.Generally, it may be desirable to configure the horn 250 to have anasymmetric mass or a center of mass off from the horn's 250 longitudinalaxis. Turning to FIG. 10 a, a horn 4000 in accordance with a preferredembodiment is shown. The horn 4000 includes a distal end 4010,configured to engage an ultrasonic needle, e.g., 210, 1000, 2000, and3000. The distal end 4010 of the horn 4000 has a diameter ofapproximately 0.146″. The horn 4000 defines a lumen 4015, whichfunctions as an aspiration line. The proximal section of the horn 4000,which has a diameter of about 0.375″, includes a notch 4020 having alength of approximately 0.1875″ and a core width of approximately0.155″. The distance between the distal end 4010 of the horn 4000 andthe distal end of the notch 4020 is approximately 1.635″. The proximalsection of the horn 4000 is coupled to a stack of piezoelectric crystalrings 4030.

Turning to FIG. 10 b, a cross-section of the horn 4000 taken alongdirection line iii is shown. In one embodiment, the notch 4020 iscreated by carving out three sides of the horn 4000 at the location ofthe notch 4020. In another embodiment, shown in FIG. 10 c, a horn 4100is shown with a notch defined by only one side. Multiple notches can becreated.

A profile of this horn's 4000 characteristics along a frequency spectrumis shown in FIG. 10 d. Phacoemulsification handpieces 200 typically havemultiple resonant frequencies. The impedance/phase profile shown in FIG.8 b is for the traditional operating frequency, e.g., in the range of 30to 40 kHz. A similar profile can be also shown at other resonantfrequencies, e.g., in the range of 20 to 30 kHz. With horn 4000, it wasdetermined that at 38 kHz, a maximum range of longitudinal vibration isprovided at the needle 210 distal tip. When the operating frequency,however, is dropped down to a lower resonant frequency, e.g., 26 kHz,both effective (sustained and substantial) transverse and effectivelongitudinal ranges of motion are provided at the needle 210 distal tip.Furthermore, depending on the shape and location of the notch 4020formed on the horn 4000, an additional transversal node can be createdon the frequency spectrum, e.g., point D (which was determined to beabout 28 kHz with horn 4000, where the operating frequency at point Dcauses the needle 210 distal tip to vibrate predominantly in thetransverse direction, e.g., x and/or y direction. The location of thetransversal node, point D, relative to the resonant frequencies, isdependent upon the horn configuration and material, and can even be usedto coincide with a resonant frequency, thereby enhancing transversalmotion at that frequency.

The following are other horn configurations that can provide the profilediscussed above and shown in FIG. 10 c. Turning to FIG. 11, another horn4500 configuration is shown having a notch 4510, wherein the notch 4510is filled with an acoustic material known in the art, such as silicon.

Turning to FIG. 12, another horn assembly 5500 is shown having the hornbody 5560 and piezocrystal crystal stack 5570 define a lumen 5550 thatis off from the horn's 5500 central longitudinal axis.

Turning to FIG. 13, another horn assembly 5700 is shown having thepiezocrystal stacks 5710 with staggered slightly.

Accordingly, with a phacoemulsification handpiece 200 constructed with ahorn 4000, 4500, 5500, 5700, the control unit 102 can be configured toprovide three types of vibration for the ultrasonic needle, 210, 1000,2000, or 3000, (1) longitudinal, (2) transversal, and (3) a hybrid witheffective transversal and effective longitudinal motion. Furthermore,the control unit 102 can also apply variations of these modes in pulses,as described in U.S. Pat. No. 7,169,123, wherein a single pulse ofenergy with a single operating frequency applied to the needle can causedistal end of the needle 210, 1000, 2000 or 3000 to vibrate in eitherthe longitudinal direction, transversal direction, or both, and furtherwherein different pulses causing different types of vibration that canbe juxtaposed and controlled by the surgeon, e.g., the interface device140 such as a computer or the footswitch 26, 80. The pulses describedabove can further be shaped, as described in U.S. patent applicationSer. No. 10/387,335 to Kadziauskas et al., which is hereby incorporatedby reference in its entirety.

In the foregoing specification, the invention has been described withreference to specific embodiments thereof. It will, however, be evidentthat various modifications and changes may be made thereto withoutdeparting from the broader spirit and scope of the invention. Forexample, the reader is to understand that the specific ordering andcombination of process actions described herein is merely illustrative,and the invention may appropriately be performed using different oradditional process actions, or a different combination or ordering ofprocess actions. For example, this invention is particularly suited forapplications involving medical systems, but can be used beyond medicalsystems in general. As a further example, each feature of one embodimentcan be mixed and matched with other features shown in other embodiments.Additionally and obviously, features may be added or subtracted asdesired. Accordingly, the invention is not to be restricted except inlight of the attached claims and their equivalents.

1. A handpiece for phacoemulsification, comprising: a needle, whereinthe needle has a distal end and a proximal end, wherein the distal endof the needle is configured to vibrate in at least a transversedirection when power is applied to the handpiece; and a horn, whereinthe horn has a distal end configured to engage the proximal end of theneedle and wherein the horn has one or more notches distributed aroundan outer surface of the horn.
 2. The handpiece of claim 1, wherein theat least one of the one or more notches is substantially asymmetric. 3.The handpiece of claim 2, wherein there is a single notch on a singleside of the horn.
 4. The handpiece of claim 1, wherein a distancebetween the distal end of the horn and the one or more notches isapproximately 1.635 inches.
 5. The handpiece of claim 1, wherein atleast one notch has a length of about 0.1875 inches.
 6. The handpiece ofclaim 1, wherein at least one notch has a core diameter of about 0.155inches.
 7. The handpiece of claim 1, further comprising one or morepiezoelectric rings, wherein the one or more piezoelectric rings arecoupled with the proximal end of the horn.
 8. The handpiece of claim 7,wherein the horn and the one or more piezoelectric rings define a lumen,wherein the lumen is off-set from a central longitudinal axis of thehorn.
 9. The handpiece of claim 8, wherein the one or more piezoelectricrings are in a stacked formation, wherein the one or more piezoelectricrings in the stacked formation are staggered.
 10. The handpiece of claim1, wherein the handpiece is configured to operate at a frequency between20 kHz and 40 kHz.
 11. The handpiece of claim 10, wherein the frequencyis between 20 kHz and 30 kHz.
 12. The hand piece of claim 10, whereinthe frequency is between 30 kHz and 40 kHz.
 13. The handpiece of claim1, wherein at least one notch is configured and dimensioned to createtransversal vibration at the distal end of the needle between 26 kHz and38 kHz.
 14. The handpiece of claim 13, wherein the transversal node isat about 28 kHz.
 15. The handpiece of claim 1, wherein at least onenotch is configured and dimensioned to create a transversal node that isa resonant frequency.
 16. A handpiece for phacoemulsification,comprising: a needle having a distal end, wherein the distal end of theneedle is configured to vibrate in a transverse direction when power isapplied to the handpiece.
 17. The handpiece of claim 16, wherein thepower is a single effective operation frequency.
 18. The handpiece ofclaim 16, wherein the needle is substantially straight and has a centerof mass that is offset from a longitudinal axis of the needle.
 19. Thehandpiece of claim 16, wherein the needle further comprises a needlebase, wherein the needle base is substantially asymmetric.
 20. Thehandpiece of claim 16, wherein the needle further comprises a needlebase, wherein the needle base is substantially asymmetric and whereinthe needle is substantially straight.
 21. The handpiece of claim 19,wherein the needle base has an asymmetric configuration along alongitudinal axis of the needle.
 22. The handpiece of claim 19, whereinthe needle base has a substantially flattened side along a longitudinalaxis of the needle.
 23. The handpiece of claim 19, wherein across-section of the needle base along a longitudinal axis of the needlehas a substantially crescent shape.
 24. The handpiece of claim 19,wherein a cross-section of the needle base has a lumen offset from acenter line of a longitudinal axis of the needle.
 25. The handpiece ofclaim 16, wherein the needle further comprises an interface adaptor,wherein the interface adaptor is off-center from a center line of alongitudinal axis of the needle.
 26. The handpiece of claim 16, whereinthe needle further comprises an interface adaptor, wherein the interfaceadaptor is concentric with a lumen of the needle and off-center withrespect to a center line of the lumen along a longitudinal axis of theneedle.
 27. The handpiece of claim 16, wherein the needle comprises alumen and an outside wall that is parallel with the longitudinal axis ofthe needle, and wherein the lumen is angled with respect to thelongitudinal axis of the needle.